Sciatica (also known as lumbosacral radicular syndrome, ischias, nerve root pain, and nerve root entrapment) is pain in the distribution of the sciatic nerve, ie felt in the thigh and, most importantly, below the knee (1). A pain that is not felt below the knee is not sciatica. Characteristically sciatica is exacerbated by coughing, straining, sneezing, or laughing (2).
The lifetime incidence of sciatica varies from 13-40% while the annual incidence of an episode of sciatica can be between 1-5% (2).
Sciatica is rarely due to a sciatic nerve disorder. It is usually referred pain, either from the dural sleeve of a lumbar or sacral nerve root, or, from an abnormal joint:
- dural root pain:
- intense pain
- often accompanied by numbness and paraesthesia
- joint or ligament pain:
- inconstant pain
- usually no neurological signs
- an estimated 5%-10% of patients with low back pain have sciatica
- annual prevalence of disc related sciatica in the general population is estimated at 2.2%